The disclosure relates to an apparatus and method of analyzing borehole images. More specifically, this disclosure relates to automatically dip picking on borehole images.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
A well drilled through a geological formation may pass through numerous strata of different types of rock. The interfaces between different strata of the formation may be referred to as bed boundaries. The bed boundaries form part of the structure of the geological formation. Knowing the placement of the bed boundaries in the geological formation thus may help locate zones of interest, such as those that contain oil, gas, and/or water.
When imaging the borehole, geological planar surfaces (bed boundaries, fractures, faults, etc.) appear in the image as sinusoids and are called “dip”. A dip is defined relative to a predetermined system of coordinates associated to the tool by two angles (apparent dip angle or apparent inclination relative to the axis of the borehole and apparent azimuth angle relative to a north axis projected on a tool section) and by a measured depth (curvilinear length of the borehole). The dip may also be converted in a “true” coordinate system (zenith, east, north) and in “true” depth using measurements performed in or near the borehole. In the following, the dip is always expressed in the apparent coordinates system (i.e. associated to the tool) and “dip angle”, “inclination” or “azimuth angle” refers to “apparent dip angle”, “apparent inclination” or “apparent azimuth angle”.
The apparent formation dip, may be particularly useful both for drilling into the stratum of the formation where the zone of interest is located, as well as for locating the placement of the bed boundaries throughout the geological formation. Although there may be a variety of downhole tools that can image the wellbore, identifying formation dips from a borehole image in an accurate and time-efficient manner may prove to be a challenge.